1. Field of the Invention
The present invention relates to a brake system of a vehicle. More particularly, it relates to an antiskid control device to prevent wheels of the vehicle from locking when the brake system is operated, so that drivability of the vehicle is maintained.
2. Description of the Related Art
In a brake system of a vehicle, a master cylinder connected to a brake pedal and a wheel cylinder provided in a brake mechanism of the wheel are connected to each other by a piping system. An antiskid control device, as disclosed in Japanese Examined Patent Publications Nos. 49-28307 and 49-32494 for example, has a construction in which, in the piping system, a valve for discharging pressurized oil from the wheel cylinder and a pump for supplying pressurized oil into the wheel cylinder are provided. Thus, when a locking condition of the wheel is sensed, the pressurized oil in the wheel cylinder is quickly released, then, when the wheel returns to a braking condition, the pump gradually supplies pressurized oil to the wheel cylinder.
However, in this brake system, when an antiskid control is carried out, a part of the pressurized oil discharged from the pump flows into the master cylinder, causing pressure pulsations in the master cylinder. As a result, a kickback phenomenon, in which the brake pedal is pushed back against the foot of the driver by the pressure in the master cylinder occurs, and an unpleasant feeling is given to the driver.